Condition responsive apparatus

A condition responsive apparatus having a control member movable in response to a pre-determined physical condition, comprising:

• an optical coupler including a solid state light source and a detector;
• a vane attached to said control member for movement therewith between said light source and said detector from a first position to a second position in response to a change in the physical condition;
• a trigger circuit having an input for receiving a drive voltage and in response thereto generating a control signal;
• a coupling circuit connected to said detector and in response to movement of said vane from the first position to the second position generating the drive voltage above a threshold level to the input of the trigger circuit, said trigger circuit generating the control signal in response to the drive voltage above the threshold level;
• and
• control means including a control transistor having an input electrode connected to said trigger circuit and in response to the control signal generating an output signal indicating movement of the control member in response to a change in physical condition.

A condition responsive apparatus, comprising:

• a pressure gauge having a Bourdon tube expandable in response to an external pressure;
• an optical coupler including a solid state light source and detector;
• a vane attached to said Bourdon tube for movement between said light source and said detector from a first position to a second position in response to said external pressure;
• a pulse generating circuit;
• a voltage divider responsive to movement of said vane from said first position to said second position for connecting an output signal from said detector to said pulse generating circuit, said pulse generating circuit generating a control signal in response thereto;
• control means connected to said pulse generating circuit for receiving said control signal and in response thereto generating an output signal;
• and
• power means connected to said control means for applying said output signal to a load.

A condition responsive apparatus, comprising:

• a pressure gauge having a Bourdon tube expandable in response to an external pressure;
• an optical coupler including a light-emitting diode and a Darlington amplifier detector, said Darlington amplifier detector including an input photo-transistor and an output driver transistor;
• a vane attached to said Bourdon tube for movement therewith between said light-emitting diode and said photo-transistor from a first position to a second position in response to said external pressure;
• a pulse generating circuit having an input connected to a voltage node, said voltage node being further connected to an emitter terminal of said output driver transistor;
• a voltage divider having first and second arms, said first arm including a first resistor and said Darlington amplifier, said second arm having a second resistor, said first and second arms connected at said voltage node and serving to connect said output driver transistor to said pulse generating circuit, said pulse generating circuit generating a control signal in response to movement of said vane from said first position to said second position;
• a control transistor connected to said pulse generating circuit for receiving said control signal and in response thereto generating an output signal indicating movement of said vane in response to said external pressure;
• and
• a power transistor connected to said control transistor for applying said output signal to a load.

A condition responsive apparatus, comprising:

• a pressure gauge having a Bourdon tube expandable in response to an external pressure;
• an optical coupler including a solid state light source and a detector;
• a vane attached to said Bourdon tube for movement between said light source and said detector from a first position to a second position in response to the external pressure;
• a Schmitt trigger circuit having an input for receiving a drive voltage and in response thereto generating a control signal;
• a coupling circuit connected to said detector and in response to movement of said vane from the first position to the second position generating the drive voltage above a threshold level to said Schmitt trigger circuit, said Schmitt trigger circuit generating a control signal in response to the drive voltage above the threshold level;
• and
• control means connected to said Schmitt trigger circuit and in response to the output control signal therefrom generating an output signal to a load.

A condition responsive apparatus, comprising:

• a pressure gauge having a Bourdon tube expandable in response to an external pressure and including an indicator responsive to the expansion of the Bourdon tube;
• an optical coupler including a light emitting diode and a Darlington amplifier detector, said Darlington amplifier detector including an input photo transistor and an output driver transistor;
• a vane attached to said Bourdon tube for movement therewith between said light emitting diode and said photo transistor from a first position to a second position in response to a change in external pressure;
• a Schmitt trigger circuit having an input connected to a voltage node for receiving a drive voltage and in response thereto generating a control signal, said voltage node being further connected to the output driver transistor;
• a coupling circuit connected to the output driver transistor of said Darlington amplifier detector and in response to movement of said vane from the first position to the second position generating the drive voltage above a threshold level to said Schmitt trigger circuit, said Schmitt trigger circuit generating the control signal in response to the drive voltage above the threshold level;
• control means connected to said Schmitt trigger circuit and in response to the control signal generating an output signal;
• and
• power means connected to said control means for applying the output signal to a load.